This program of research involves short- and long-term longitudinal studies in Goteberg (Sweden) and Berlin (Germany) of children with distinct child care experiences. The longitudinal study in Sweden was initially designed to elucidate the effects of early care arrangements on the development of 145 children recruited in 1982 at an average age of 16 months. Initial analyses indicated that the quality of home care and the quality of alternative care had substantial effects on the children's verbal abilities, social skills, and personal maturity. The effects diminished as the children moved into the formal educational system and their individual personalities came to affect the adjustment to school. Preliminary analyses revealed no apparent effects of contrasting early care patterns on educational histories and the psychological status of these children at 15 years of age. Longitudinal analyses revealed substantial stability over time in the children's personality styles. Of the Big Five personality factors, conscientiousness was coherent from toddlerhood, whereas the internal reliabilities of extraversion, agreeableness, neuroticism, and openness to experience increased over time. Scores on most of these factors were fairly stable over time, but children became less extraverted, more agreeable, and more conscientious with age. Although individual differences were stable, the children also became more ego-controlled over time. Boys' levels of ego resiliency were more stable over time than girls'; boys became less resilient from middle childhood into mid adolescence, whereas girls became more ego-resilient as they entered adolescence. Participants in the study were reinterviewed in 2003-2004, when they average 21 years of age and are currently being analyzed. In the Berlin longitudinal study, we have been measuring the psychophysiological, socioemotional, and behavioral tendencies of infants so that we can assess the effects of earlier individual differences in behavioral and psychophysiological reactivity and infant-mother attachment on the adaptation to out-of-home center care. During an adaptation phase, in which mothers remained in the centers with their toddlers, secure infants had markedly lower cortisol levels than insecure infants, suggesting that they gained more protective support from the presence of their mothers. When the mothers stopped remaining with their infants, the cortisol responses of the securely attached toddlers were much more dramatic than the responses of the insecurely attached toddlers: on the initial separation days, cortisol levels rose over the first 60 minutes after arrival to levels twice as high as those at home. Secure toddlers also fussed/cried upon separation more than insecurely attached toddlers. Cortisol and behavioral markers of distress were correlated in securely attached but not in insecurely attached toddlers. The security of attachment changed in many cases following the onset of child care, but attachments were more likely to become or remain secure when mothers remained longer in the child care facilities with their toddlers. Close examination of individual differences in cardiac reactivity and of the formation of relationships with care providers are now under way.